Amine alginate product and process



Patented May 16, 193

AMINE ALGINATIE PRODUCT AND PROCESS Bennett Preble, National City,Calif., assignor to Kelco Company; Los Angeles, Calif a corporation ofDelaware No Drawing. Application October 22, 1935,

Serial No. 46,213

11 Claims.

This invention provides new alginate products and processes of producingsame. Its principal object is to produce water soluble hydroxy aminealginate compositions by mixing alginic acid with a water solublehydroxy amine in their respective combining proportions to form aproduct having many novel and valuable properties, rendering it usefulfor many purposes in the arts.

I have discovered that triethanolamine, diethanolamine andmonoethanolamine may be used in producing water soluble products fromalginic acid. Furthermore, since triethanolamine is a hydroxy'amine,other hydroxy amines, such as tripropanolamines, dipropanolamines andmonopropanolamines may replace any of the ethanolamines. Complicatedhydroxy amines for example the butanolamines, may'be used. In addition,amines other than hydroxy amines, for example, simple aliphatic,tertiary, secondary or primary amines, such as tripentyl amines,dipentyl amines and monopentylamines, also substituted amines, includingchlorinated amines, may replace triethanolamine. These replacements ofethanolamines may be complete or partial or may be made by more than oneamine.

Commercial monoethanolamine is principally.NI1zCzI-I4OH(2-amino-ethanol); commercial diethanolamine is mainlyNH(C2H4OH) z; and com;- mercial triethanolamine is mainly N(C2H4OH)(pgs,5"-trihydroxytriethylamine) The commercial grade of each of thesecontains a small amount of the other two, but so far we have found thebest results are obtained for our purposes when using triethanolamine.

When technical triethanolamine and alginic acid are mixed in theapproximate proportions of their respective equivalent weights a neutralproduct is obtained and hence the reaction which occurs when alginicacid and triethanolamine are mixed is probably expressed, as far as Ihave at present been able to ascertain, by the following theoreticalequation:

Triotliunolmnino Alginic acid The alginic acid used in manufacturingthis composition may be any alginic acid, although I prefer thatmanufacture by-the method disclosed in the Thornley 8; Walsh U. S.Letters Patent No. 1,814,981 issued July 14, 1931; or the Clark 8: Greenapplication Serial No. 693,891, filed October 16, 1933; or the Greenapplication Serial No. 721,829, filed April 21, 1934, since the alginicacid made by any of the saidmethods is relatively pure.

The following is one method for preparing the composition: f

(A) Approximately 1000 lbs. of wet alglnic acid manufactured by themethod disclosed in the above mentioned Clark and Green application,Serial No. 693,891, is placed in a dough or other suitable paste mixer.This acid would contain about 10% (or 100 lbs.) of dry material if allthe water were evaporated. The mixer is started and approximately 80lbs. of commercial tri ethanolamine is added slowly. The triethanolaminereacts almost immediately on the fibrous mass in the mixer to produce astifl or heavy paste. After about minutes of mixing the reaction iscomplete and a dilute solution of the paste Will have a pH value ofapproximately 7.

This composition is relatively pure triethanolamine alginate.

Triethanolamine alginate paste in comparison with pastes made from gums,gelatin, casein, 'etc.'; will not spoil easily since it is resistant'to' the:

action of molds and micro-organisms which produce liquefaction anddecay, and therefore molds grow or develop thereon very slowly; and suchpaste, if stored at temperatures below 40 degrees Fahrenheit or if somepreservation such as formaldehyde is added thereto, may be preservedindefinitely.

To obtain an ethanolamine alginate composition of desired consistency, Imay use an acid whose ammonia salt when in a 2% aqueous solution has aviscosity ranging from one to several Triethanolamine alginate Molecularand equivalent wciglit=1-i9 Equivalent weight=176 Equivalent wcight=325The triethanolamine I have used in the manufacture of this compositionis a commercial grade made by the Carbide and Carbon ChemicalCorporation, and consists of about 87% triethanolamine, 11%diethanolamine and 2% monoethanolamine.

thousand seconds, as measured by the Woolwich viscosity test. This testmeasures the time required for a 5 inch diameter steel ball to fall 15centimeters at 20 centigrade. Specific examples of how the viscosity ofour triethanolamine' alginate may be controlled are given in the fol-,

lowing table showing how different acids give triethanolamine alginatesof different. viscosities:

Resulting tri- ;gg ethanolamino zn r iium salt ga a so u on gives a gigives a viscosity 0 of about- A triethanolamine alginate having 4seconds viscosity on a 2% solution will dry to produce a good film,whereas a triethanolamine alginate with 800 seconds viscosity would haveto be diluted to such an extent that the resulting film would not givethe desired results. Triethanolamine alginate having a higher viscosityis more desirable for some purposes, such as for producing a strongerfilm. Moreover, a high viscosity triethanolamine alginate has lesstendency to run off the surface to which it is applied before becomingdry.

t hich ammonia ma 're-... (B) me mam w y an 90 1105.: triethanolamineadded, resulting place part of the triethanolamine to control theconsistency and nature of a dried film approxi- 'mately 1000 lbs. of wetalginic acid manufactured by the Clark & Green method (application Ser.No.'.693,891) is placed in a .dough mixer as described in example (A),and '70 lbs. of commercial triethanolamine is slowly added along withlbs. of 26 Baum aqua ammonia. After about 30 minutes of mixing(different types of mixers will naturally require more or less time) theresulting product as'a pH between '7 and 8 is an'ammonium-triethanolamine alginate. This gives a film of mediumpliability which dries faster.

When it is desired to produce a composition having a softer and moreflexible film, this may be done by adding more than the combiningchemicalequivalent weight of triethanolamine so that the pH of a watersolution of the paste is higher than 7. We have found 8.0 pHparticularly useful.

Sometimes when a smaller amount of triethanolamine is. used so that thepH of the resulting paste is 6.0 or below such composition is a stifferpaste or'has a higher viscosity for a given concentration than one sayof'7.0 pH and therefore has certain advantages for particular uses.

The pH of these triethanolamine alginate products will range between pH3 and pH 11.

When a film of triethanolamine alginate is dried it is smooth, soft andflexible, and feels plump to the fingers, is strong, and Will not crackwhen bent sharply, and is readily soluble in water but insoluble in oilsand greases.

The above enumerated properties are in sharp contrast to those of otheralginate salts, such as sodium or ammonium alginates, which formrelatively brittle hard films which will crack when bent sharply andwhich therefore cannot be successfully utilized. Because of its stronglyadhesive properties the triethanolamine alginate may be used for coatingpractically all solid surfaces such as cheese, meats and other foodproducts, glass, metals, wood, plastics, cerarhicyvare and plaster.

For greater ease in shipping and handling the triethanolamine alginatemay be produced in a dry form by putting the pastes 'hereinbeforedescribed in amechanical drier of any conventional type, such as a drumdrier. After drying, the product is reduced by means of a chopper ormill to a particle size that can be conveniently dissolved in water. Insome cases the paste might be converted into a dilute solution and thendried by means of-a spray drier.

Dry product (C) The following is one method for producing the product indry form: Approximately 1000 lbs. of wet alginic acid is placed in atank and diluted with water to about 1000 gallons. This mixture is thenagitated while 80 lbs. of triethanolamine is added. The result is abouta 2% solution of triethanolamine alginate. This mixture is then spraydried to give a fine powder containing 8.0% triethanolamine al'ginateand water.

(D) Triethanolamine 'alginate may be produced by first drying thealginic acid and then adding triethanolamine to it; as for example:

. Approximately 1000 lbs. of wet alginic acid containing about 10% (or100 lbs.) of dry material (if all the water was evaporated) is placed ontrays and set in the sun until dried down to about 125 lbs. Thismaterial is ground to pass through a mesh screen, and then placed in amixer,

in very stiff crumbly material having a pH of about 9.5 when made into a2% solution. This method takes longer to complete, but produces a goodcomposition. This method reduces the viscosity of the product as dryingthe alginic acid reduces the viscosity of the resulting salts made. fromthe acid, which reduction in viscosity is fructose, maltose, zylose,glycerin, or mixtures of these with each other; also gelatin and gluewhen so treated that they will not react with the triethanolaminealginate, may be used. Instead of glycerin I may add other polyhydroxycompounds, such as sorbitol or some. dihydroxy compound such asethylene, glycol, propylene glycol, or other glycol.

It is possible to replace a part of the triethanolamine by other basicsubstances and produce a composite composition containing some sodium,ammonium, aluminum, zinc, potassium or alkali earth metals.

The dried triethanolamine alginate product can be made to dissolve inwater even when calcium salts or other salts which form insolublealginates are present, by adding to the triethanolamine anamount oftrisodium phosphate equivalent to 4 to 10 percent of the weight of theanhydrous alginic acid. In place of trisodium phosphate its equivalentsmay be used, such as disodium phosphate, ammonium phosphate,

sodium carbonate, and other salts of acids which form insoluble calciumsalts.

If desired a preservative may be incorporated in the composition; forexample (E) Approximately 1000 lbs. of wet alginic alg'inate salt.

' alginic acid.

4 aisacee acid is placed in a dough mixer and 60 lbs. of

triethano'lamine is added to forma wet paste containing partiallyneutralized alginic acid. The pH of such a paste is approximately 6. Tothis paste 14 lbs. of formaldehyde is added as a preservative. Besidesformaldehyde, other preservatives, including sodium benzoate, phenol,sodium phenyl phenolate, may be used.

I have also found that it is possible to replace part of thetriethanolamine by other basic substances and produce a compositecomposition containing some sodium, ammonium, potassium or other metalwhich could form a water soluble Furthermore, combinations may be madewith metals which form water insoluble alginates such as zinc; calcium,aluminum, copper or the like. In such a compound, one or more of theacidic hydrogen atoms of the complicated alginic acid molecule(CSH'ZO4COOH)1: may be replaced by one of the metals above, instead ofbeing combined with triethanolamine to form --COONH(C2H4OH) a.

My triethanolamine alginateproduct has certain properties which havespecial merit and is superior to competitive materials, these propertiesbeing: (1) that a film is flexible and elastic; and (2) that a film iswater-soluble and swells immediately when brought into contact withwater and slowly goes into complete solution or dispersion in the water.

I claim:

1. A mixed salt'oi alginicacid consisting oi. inorganic substances andethanolamine of the formula A($)a(1l)n where A is the radical of alginicacid, selected from the group which consists of the alkali metals, thealkaline earth metals, zinc, aluminum, and copper. 1: is ethanolamine,and n is a whole number consistent with the basicity of theacid and theremaining substances. 2. A mixed ammonium-ethanolamine salt of 3. Amixed ethanolamine-alkaline earth salt of alginic acid. I

4. Aiwater soluble chemical compound of alginic acid with definitestoichiometric proportions of ethanolamine and a metal chosen from thegroup of metals consisting of the alkali metals, the alkaline earthmetals, zinc, aluminum, and copper which normally form insoluble saltswith alginic acid.

5. A water soluble chemical compound of alginic acid with definitestoichiometric proportions of triethanolamine and a metalpchosen fromthe group of metals consisting of the alkali metals, the alkaline earthmetals, zinc, alumium, and copper which normally form insoluble saltswith alginic acid.

6. The process of preparing a mixed ammonium-ethanolamine salt whichcomprises mixing wet'alginic acid, ammonium hydroxide solution, andtriethanolamine, and agitating the mixture until chemical combinationoccurs. 4 '7. The processof preparing mixed ethanolamine alginate whichcomprises. mixing moist alginic acid, ethanolamine and aqua ammonia,agitating the mixture until it becomes a paste, and drying the paste.

8. The process of preparing mixed triethanolamine-alginate whichcomprises mixing 'mois't alginic acid, triethanolamine and an ammoniumsalt of a weak volatile acid and agitating the mixture until chemicalcombination occurs.

9. The process or preparing mixed ammonium triethanolamine-alginatewhich comprises mixing moist alginic acid, triethanolamine and ammoniumcarbonate and agitating the mixture 7 until chemical combination occurs.

10. The process of preparing mixed ammonium triethanolamine-alginatewhich consists in thoroughly mixing approximatelylOOO pounds of wetalginic acid containing 10 percent alginic acid solids," approximately70 pounds of triethanolamine-alginate, and 10 pounds of approximately 26degree Baume aqua ammonia 11. The process of manufacturing mixedethanolamine salts of alginic acid and metals which comprises mixingmoist alginic acid, ethanolamine and a hydroxide or a metal selectedfrom the group which consists of the alkali metals,

the alkaline earth metals, zinc, aluminum, and copper, each in itsstoichiometric proportion, and agitating the mixture until chemicalcombination occurs.

BENNETT PREBLE.

